1. Field of the Invention
This invention pertains to an attachment member for attaching a graft material to a coronary vessel.
2. Description of the Prior Art
U.S. Pat. No. 5,944,019 issued Aug. 31, 1999 teaches an implant for defining a blood flow conduit directly from a chamber of the heart to a lumen of a coronary vessel. An embodiment disclosed in the aforementioned patent teaches an L-shaped implant in the form of a rigid conduit having one leg sized to be received within a lumen of a coronary artery and a second leg sized to pass through the myocardium and extend into the left ventricle of the heart. As disclosed in the above-referenced patent, the conduit is rigid and remains open for blood flow to pass through the conduit during both systole and diastole. The conduit penetrates into the left ventricle in order to prevent tissue growth and occlusions over an opening of the conduit.
U.S. Pat. No. 5,984,956 issued Nov. 16, 1999 teaches an implant with an enhanced fixation structure. The enhanced fixation structure includes a fabric surrounding at least a portion of the conduit to facilitate tissue growth on the exterior of the implant. U.S. Pat. No. 6,029,672 issued Feb. 29, 2000 teaches procedures and tools for placing a conduit.
Implants such as those shown in the aforementioned patents include a portion to be connected to a coronary vessel and a portion to be placed within the myocardium. Most of the implants disclosed in the above-mentioned patents are rigid structures. Being rigid, the implants are restricted in use. For example, an occluded site may not be positioned on the heart in close proximity to a heart chamber containing oxygenated blood. To access such a site with a rigid, titanium implant, a very long implant must be used. A long implant results in a long pathway in which blood will be in contact with the material of the implant. With non-biological materials, such as titanium, a long residence time of blood against such materials increases the probability of thrombus. The risk can be reduced with anti-thrombotic coatings. Moreover, a rigid implant can be difficult to place while achieving desired alignment of the implant with the vessel. A flexible implant will enhance placement of the implant. U.S. Pat. No. 5,944,019 shows a flexible implant in FIG. 22 of the ""019 patent by showing a cylindrical rigid member in the heart wall and a T-shaped rigid member in the coronary artery. The cylindrical and T-shaped rigid members are joined by flexible conduit. Unfortunately, flexible materials tend to be non-biostable and trombogenic and may collapse due to contraction of the heart during systole. PCT/US99/01012 shows a flexible transmyocardial conduit in the form of a cylindrical rigid member in the heart wall and a natural vessel (artery or vein segment) connecting the rigid member to an occluded artery. PCT/US99/00593 (International Publication No. WO99/38459) also shows a flexible conduit. PCT/US97/14801 (International Publication No. WO 98/08456) shows (in FIG. 8c) a transmyocardial stent with a covering of expanded polytetrafluoroethylene.
According to a preferred embodiment of the present invention, an attachment member is disclosed for securing a graft material to a vessel. The attachment member includes a conduit portion for attachment to said graft material. The attachment member has first and second anchor wings formed on opposite sides of an end of said conduit portion. The anchor wings are biased to extend substantially perpendicular to an axis of the conduit portion. The first and second anchor wings have arcuate shapes around substantially collinear axes for the anchor wings to define a flow path within a vessel on opposite sides of the conduit portion.